Method of and means for forming or working spherical surfaces, concave or convex



Oct. 30, 1928. 1,689,928

, N. J. OLSSON METHOD OF AND MEANS FOR FORMING 0R WORKING SPHERICAL SURFACES, CONGAVE 0R convnx Filed Feb. 25, 1926 2 Sheets-Sheet 1 INVENTOR /V'/ Josef 0/5301 6 Oct. 30, 1928. 1,689,928

J oLssoN N. METHOD OF AND MEANS FOR FORMING OR WORKING SPHERICAL SURFACES, GONCAVE 0R couvEx Filed Feb. 25, 1926 2' Sheets-Sheet 2 INVENTOR mzmsefozmn @(W TTORNEY M Patented Oct. 30, 1928.

UNITED STATES PATENT OFFICE.

NILS JOSEF OLSSON, OF GOT'IENBORG, SWEDEN, ASSIGNOR TO AKTIEZBOLAGET SVENSKA. KULLAGEBFABRIKEN, OF GOTTENBORG, SWEDEN, A CORPORATION OF SWEDEN.

METHOD OF AND MEANS FOR FORMING CIR/WORKING SPHERIGAL SURFACES,

CONCAVE OR CONVEX.

Application filed February 25, 1926, Serial No. 90,453, and in Sweden March 5, 1925.

In the machines hitherto used for forming or working spherical surfaces (sphere grinding machines, etc), oscillatory members are usually employed which entail very varying bearing pressures causing detrimental vibrations.

The object of this invention is to provide a method of and means for forming or working spherical surfaces, concave or convex, in such manner as to avoid the said drawbacks.

According to thisinvention, all movable members used are continuously rotating. The improved method consists in causing either the blank (rotating, as usual, in relation to the working tool about an axis through the centre of the spherical surface) or the working tool to rotate continuously at a different speed. about an axis forming an angle with the first mentioned axis of rotation. In sphere grinding according to this method, a grinding wheel is employed which rotates about its geometrical axis while the blank rotates about an axis through the centre of the spherical surface, one of said parts (the grinding Wheel or the blank) being journaled in a continuously rotating sleeve or the like. The grinding wheel may be eccentrically adjustable in a sleeve or the like rotating about an axis passing through the centre of the spherical surface parallel to the axis of the grinding wheel, the rotary blank being mounted so as to be adjustable at a desired angle to the axis of the grinding wheel. In order to provide for the necessary feed motion, the spindle of the grinding wheel may be eccentrically journaled in a sleevemvhich is itself eccentrically mounted in an outer sleeve so that the spindle of the grinding wheel may be adjusted, by turning the inner sleeve in the outer one, at different distances from the axis of rotation of the outer sleeve. For the same purposes, the spindle of the grinding wheel may as well be axially adjustable.

In the drawing, certain means for sphere grinding according to this invention have been illustrated by way of example. Fig. 1 shows a grinding wheel and a blank in the positions which they take up whenworking. Fig. 2 shows diagrammatically how the grinding wheel may be mounted in order to admit of adjustment of the axes of rotation at different distances from each other. Figs. 3 and 4 are views, at right angles to each other, of a sphere grinding machine in accordance with the invention. Figs. 5 and 6 show various arrangements for grinding convex spherical surfaces.

Referring first to Fig. 1, the grinding wheel 1, whose working surface 2 is shaped in the form of a toric surface, "or obtains such form during grinding. rotates about two axes, viz, its geometrical axis 33. and an axis 4-4 parallel to the former and intersecting the axis of rotation 66 of the blank 5 in the centre pf the spherical surface. On account of the different speeds of rotation of the grinding wheel and the blank about the axes 44 and 6-6, respectively, the contact line between the grinding wheel and the blank will continuously move along the inner side 7 of the blank so as to make it exactly spherical in shape. In order to provide for the necessary feed motion, the spindle 8 of the grinding wheel, Fig. 2, may be eccentrically mounted in a sleeve 9 which is itself eccentrically mounted in an outer sleeve 10, so that by turning the inner sleeve in the outer one (for instance by a Worm and wheel), the spindle 8 can be adjusted at a desired distance from the axis of rotation of the outer sleeve.

In the sphere grinding machine shown in Figs. 3 and ,4. the frame 11 carries a shaft 12 having gears 121 and 122driven by change able gearing 131 and 132 from the driving shaft 13. These gears, of course, are operated in a well known manner. The outer sleeve 10 is driven by chain 14.- and chainwheels from the shaft 12. The spindle 8 of the grinding wheel, which is journaled in an inner sleeve 9, is driven by belts 16, 17; the

belt No. 17 being held taut, by a spring 15 or the like, acting on a bell crank lever 151-452, the spring being shown hooked over a pin 150 carried by the machine frame. The blank is placed in a chuck 18 driven by belting to a pulley 19 on the chuck axle. The latter is journaled in a round slide 20 carried by a movable slide 21 so that the blank can be moved towards and away from the grinding wheel and adjusted at a desired oblique angle to the spindle of the said wheel.

e arrangement according to Fig. 5 differs from'that hereinbefore described in so far that the grinding wheel acts on the outer side of the blank instead of on the inner one.

The arrangement according to Fig. 6 differs from that shown in Fig. 5 in that the grinding wheel is hollow and held on the outor side so as to work with an inner grinding surface on the outer side of the blank.

The feed may be effected in several ways; for instance, by axially moving the spindle of the grinding wheel.

It is obvious that the invention may be applied for forming or working spherical surfaces generally, whether by grinding or by turning, polishing, etc. In polishing, the tool need not rotate about its axis.

I claim:

1. Procedure for the shaping of spherical surfaces by means of three simultaneous, continuous rotations, viz the rotation of the work around an axis through the centre of the spherical surface, the rotation of the tool around its own symmetrical axis and the revolving of this latter axis around a second axis through the centre of the spherical surface with which latter axis the symmetrical axis of the tool must not coincide, characterized thereby that the axis of rotation of the work forms an angle with the second axis through the centre of the spherical surface around which the symmetrical axis of the tool revolves and that the rotation of the work and the rotation of the symmetrical axis of the tool about the second axis through the spherical surface are taking place at speeds differing from each other.

2. A rocedure for the grinding of spherical sur aces, as set forth in claim 1, in which the grinding spindle is fed toward the work by a displacement in an axial direction.

3. In a machine for the grinding of spherical surfaces by means of three simultaneous, continuous rotations, the combination with a grinding disc rotating about its geometrical axis, of means for rotating the work-piece around an axis through the centre of the spherical surface being generated, and means for revolving one of these axes around a second axis through the centre of the spherical surface with which latter axis the symmetrical axis of the tool does not coincide, characterized thereby that the axis of rotation of the work-piece forms an angle with the second axis through the centre of the spherical surface around which the symmetrical axis of the grinding disc revolves and that the rotation of the work and the rotation of the symmetrical axis of the tool about the second axis through the spherical surface are taking place at speeds differing from each other.

4. In a machine for the grinding of spherical surfaces by means of three simultaneous, continuous rotations, the combination with a grinding disc rotating about its geometrical axis, of means for rotating the work-piece around an axis through the centre of the spherical surface being generated, and means for revolving one of these axes around a second axis through the centre of the spherical surface with which latter axis the symmetrical axis of the tool does not coincide, characterized thereby that the axis of rotation of the work-piece forms an angle with the second axis through the centre of the spherical surface around which the symmetrical axis of the grinding disc revolves, an eccentric sleeve carrying the axis of one of the aforementioned parts, and means for continuously rotating such sleeve at a speed differing from the speed of rotation of the work.

In testimony whereof I have signed my name.

'NILS JOSEF OLSSON. 

